I would work on your self image. There are many ways to do that but one of the most useful I found was mirror talk.
It is easy to feel undervalued when standing alone for a M. But the M/R does not define you.you are much more than that.
One last point. It is mentioned in a lot of places to avoid arguing with WAS as it only creates negativity and resentment that convinces them they are right to want out. I agree with that BUT don't accept disrespectful treatment. That should come more naturally when you manage to improve your self image. But would do no harm to look into this too.
Best wishes
R 25 years M 14 years S11 & S13 Working on it alone since Oct 2014 M in trouble a lot earlier (~2 years) Feb 2016. 1st R chat in a yr. Next R chat Aug'17 Still together